J.D. Dana on some modern Calcareous Rock-formations, 415 
_ only 36°34 and 42-85 for the minimum and maximum of vola- 
tile matter. Whence this discrepancy? What has become of 7-65 
per cent, of volatile matter in one case, and 2-66 in the other? 
If, again, we deduct the total amount of water and organic mat- 
ter as determined by special analyses, namely 2°33 p. ¢, and 3-91 
p.c., from the total of volatile matter, it leaves 41-66 and 41-60 
per cent., being a little more carbonic acid than the minimum of 
lime requires, and about what the maximum demands, to form a 
neutral carbonate. The author says that “the carbonic acid was 
determined in an evolution flask-glass: the results with different 
specimens varied greatly and are far from being satisfactory ;” and 
so we think, especially for basing any deductions with regard to 
the presence of hydrate of lime. : 
ther points might be touched upon. We merely allude to a sin- 
gular discrepancy in the results on page 250. The loss by pro- 
longed ignition, or amount of volatile matter, is stated as follows: 
I. 0-8270 gr. lost 0-4870 gr.—IL. 1-9020 gr. lost 0:8000 gr. 
The proportion hence deduced is 59 and 42 percent. But, a few 
lines below, the author gives as the total volatile matter A117, 
_ We pass now to the point of the theory (see page 248); and 
it is no fault of ours if it prove to be at variance with the known 
principles of chemistry. We take no pleasure in this criticism of 
a note to a former page of this volume. 
_ the author the privilege of presenting his v 
feels bound to express his dissent, and that of the editors, from 
the errors which, either from oversight or otherwise, are con- 
tained in his paper. 
We wold sek How can orgatic gan pe egrtimns Peg = 
oxygen, hydrogen, nitrogen and sulphur, when this matter 
Sraces of Meee Sree pure sulphuretted hydrogen and not 
hydrosulphuret of ammonium? But suppose that the pure sul- 
phuretted hydrogen is evolved: Would it under the circumstances 
change to sulphuric acid? Suppose it to change to sulphuric 
acid, and this to combine with lime to form the sulphate of lime, 
as the theory states: Is it then possible that uncombined ammo- 
ia should be formed from animal matter containing the elements 
of both carbonic acid and sulphuretted hydrogen? Such a su 
Version of chemical laws can hardly be e 
benefit of the coral reefs of Florida. 
sulphate? On the contrary, ammoni 
yarate of lime from any of its solu 
